Project description:SPO11-promoted DNA double-strand breaks (DSBs) formation is a crucial step for meiotic recombination, and it is indispensable to detect the broken DNA ends accurately for dissecting the molecular mechanisms behind. Here, we report a novel technique, named DEtail-seq (DNA End tailing followed by sequencing), that can directly and quantitatively capture the meiotic DSB 3’ overhang hotspots at single-nucleotide resolution.
Project description:We assembled a quantitative map for the abundance and interactions of 16 factors related to PCH in living cells and found that stably bound complexes of the histone methyltransferase Suv39h1/2 demarcate the PCH state. From the experimental data we developed a predictive mathematical model that explains how chromatin-bound Suv39h1/2 complexes act as nucleation sites and propagate a spatially confined PCH domain with elevated histone H3 trimethylation levels via chromatin dynamics. Enrichment of HP1, Suv39h1/h2, H3K9me3 and H3K36me3 was assessed by ChIP-seq in NPCs derived from ESCs showing differential occupation at intergenic major satellite repeats and enrichment of heterochromatin factors. ChIP-seq of HP1, Suv39h1, Suv39h2, H3K9me3, H3K36me3 in NPCs
Project description:HeLa cells were transiently transfected with siRNA against SUV39H1, a histone H3K9 methyltransferase. Several genes were significantly up- or down-regulated. HeLa cells were transiently transfected with siRNA against SUV39H1 or negative control siRNA. Then total RNA was extracted.
Project description:The goals of this project are to study the transcriptome profiling (RNA-seq) of mouse embryonic stem cells by histone mutants incorporation (H3.1K3M, H3.1K36M vs H3.1wt) or shRNA-mediated knockdown of methyl-transferase Suv39h1/h2 (shSuv39h1, shSuv39h2 vs shNC)
Project description:Kynureninase is a member of a large family of catalytically diverse but structurally homologous pyridoxal 5'-phosphate (PLP) dependent enzymes known as the aspartate aminotransferase superfamily or alpha-family. The Homo sapiens and other eukaryotic constitutive kynureninases preferentially catalyze the hydrolytic cleavage of 3-hydroxy-l-kynurenine to produce 3-hydroxyanthranilate and l-alanine, while l-kynurenine is the substrate of many prokaryotic inducible kynureninases. The human enzyme was cloned with an N-terminal hexahistidine tag, expressed, and purified from a bacterial expression system using Ni metal ion affinity chromatography. Kinetic characterization of the recombinant enzyme reveals classic Michaelis-Menten behavior, with a Km of 28.3 +/- 1.9 microM and a specific activity of 1.75 micromol min-1 mg-1 for 3-hydroxy-dl-kynurenine. Crystals of recombinant kynureninase that diffracted to 2.0 A were obtained, and the atomic structure of the PLP-bound holoenzyme was determined by molecular replacement using the Pseudomonas fluorescens kynureninase structure (PDB entry 1qz9) as the phasing model. A structural superposition with the P. fluorescens kynureninase revealed that these two structures resemble the "open" and "closed" conformations of aspartate aminotransferase. The comparison illustrates the dynamic nature of these proteins' small domains and reveals a role for Arg-434 similar to its role in other AAT alpha-family members. Docking of 3-hydroxy-l-kynurenine into the human kynureninase active site suggests that Asn-333 and His-102 are involved in substrate binding and molecular discrimination between inducible and constitutive kynureninase substrates.